Stevo F Posted January 31, 2020 Share Posted January 31, 2020 I've noticed that when I shut off my wagon ('98 Legacy L with 2.2 liter & automatic) I can hear the cooling fan shutting off as well. Sure enough the fan on the passenger's side is running any time the engine has warmed up, even on a cold day. It's been doing this for a few months now. I'm thinking the coolant temperature sensor is causing the fan to kick in at too low a coolant temperature. Otherwise the cooling system is in good shape- the engine temperature is right where it should be and doesn't fluctuate, no coolant leaks, etc... My problem is that I can't find the sensor. I've read up on it and seen some pictures online, but none of the pics look like what's on my car. I know it's on or beneath the intake manifold, near the IACV and the sensor for the temp gauge is next to it. Does anyone have a better way to locate it on an EJ22, or have some pictures showing it's location? Link to comment Share on other sites More sharing options...
Rampage Posted January 31, 2020 Share Posted January 31, 2020 You are in the right area. Both temp sensors are located side by side on the coolant pipe under the intake. The two pin sensor is in a little further from the single pin one. The one with two pins is the one you want to change. That goes to the ECU. The single terminal one is for the gauge. 1 Link to comment Share on other sites More sharing options...
Rampage Posted January 31, 2020 Share Posted January 31, 2020 I have a question for you. Do both fans run when you turn on the A/C? Link to comment Share on other sites More sharing options...
Stevo F Posted January 31, 2020 Author Share Posted January 31, 2020 Actually I always thought both fans always ran together but my passenger's side runs for cooling the radiator and the driver's side fan runs when the A/C is on- I believe this is normal. Link to comment Share on other sites More sharing options...
Stevo F Posted January 31, 2020 Author Share Posted January 31, 2020 7 minutes ago, Rampage said: You are in the right area. Both temp sensors are located side by side on the coolant pipe under the intake. The two pin sensor is in a little further from the single pin one. The one with two pins is the one you want to change. That goes to the ECU. The single terminal one is for the gauge. I tried looking at the coolant pipe (is this where the upper radiator hose attaches?) but it pretty much disappears under the intake manifold and I don't see either of the two sensors. Link to comment Share on other sites More sharing options...
Rampage Posted January 31, 2020 Share Posted January 31, 2020 It is number 1 in the photo. 2 Link to comment Share on other sites More sharing options...
Rampage Posted January 31, 2020 Share Posted January 31, 2020 8 minutes ago, Stevo F said: Actually I always thought both fans always ran together but my passenger's side runs for cooling the radiator and the driver's side fan runs when the A/C is on- I believe this is normal. Most of the 90s run both fans on low and both on high when needed. You have "one of the few" like our 97 that only runs one fan on low. If you look at the wiring diagram it will show that both fans should run on low speed. I found a tech article that stated "some" only run one fan on low speed. What they did was reverse the switching order of the two pins from the ECU that control the fan relays. I was ready to swap out our ECU until I found that article. Link to comment Share on other sites More sharing options...
Numbchux Posted January 31, 2020 Share Posted January 31, 2020 Plug an OBD reader in and read the coolant temperature, and compare it to an infrared temp scanner pointed at the coolant bridge (if you don't have these tools, combined investment of $20-30 on amazon and invaluable diagnostic tools). If they agree, that's not your problem. Then connect the test mode connectors to make sure the circuit operates as it should. A/C will warrant fan operation, and defrost engages A/C. Depending on the conditions, it's not improbable that the engine really is warm enough to warrant low speed fan operation. 1 Link to comment Share on other sites More sharing options...
Stevo F Posted February 2, 2020 Author Share Posted February 2, 2020 I piled around a bit and easily found the sensor once I removed the vacuum and front coolant hoses from the IACV and removed the intake from the MAF. I was trying to see if I could disconnect the connector and ended up popping the plastic part of the sensor out so it looks like I have to replace it anyway. I decided to order one from Rock Auto which will arrive tomorrow, so we’ll see if it fixes the issue- if not I’m out $11 for the new sensor Link to comment Share on other sites More sharing options...
Stevo F Posted February 4, 2020 Author Share Posted February 4, 2020 Put in the new coolant temp sensor but no difference in the fan operation. It kicks on after a few miles and appears to stay on. Again, it's just the passengers' sa(right) side fan on my car and the other fan is activated when the A/C is turned on. It must be some other electrical issue. Link to comment Share on other sites More sharing options...
Rampage Posted February 4, 2020 Share Posted February 4, 2020 As Numbchux said, plug in a scanner bring up live data, select engine temp, and go for a ride. See what the ECU says the temp is. If it is around 203 F. then the ECU will turn the fan on. To find out if "both" fans are capable of low and high speed do the following. Under the steering wheel are two green connectors. Connect them but do not make it click, they are hard to separate once they latch. Turn the Ignition Switch Key to on. Do not start. After the fuel pump and some solenoids and relays click, Both fans should run together on low speed, then both on high speed. Let it cycle a few times then turn the key off and unplug the green connectors. That will prove if the relays and fan motors are working like they should. If both fans do not run low and high together, then one of the motors or a relay is bad. Next to find out if you have one of the few that only runs one fan on low, I would check pins 73 and 74 on the ECU. If the ECU is not calling for cooling both pins will be at high voltage (battery voltage). On MOST models pin 74 goes low first to run both fans on low speed. If pin 73 goes low first then only one fan will run. If the engine gets hotter or the A/C is turned on both pins 73 and 74 will go low and both fans will run at high speed. Link to comment Share on other sites More sharing options...
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